Jannik Sinner was labelled an "artificial intelligence" player by opponent Alexander Bublik after the defending US Open champion ruthlessly raced into the quarter-finals.

World number one Sinner needed only one hour and 21 minutes - the second-quickest win in the men's singles this year - to beat Kazakhstan's Bublik in a 6-1 6-1 6-1 victory.

Within minutes of his defeat, 23rd seed Bublik wrote 'AI' in a comment on the US Open's Instagram post about the result - reiterating the description he made about Sinner going into Monday's fourth-round match.

Bublik is one of only two men to beat Sinner this season, but the 24-year-old Italian ensured there was no chance of a repeat with a ruthless performance in New York.

"We had some tough battles this year, but we know each other's game really well," said Sinner, who has already won the Australian Open and Wimbledon titles this year.

"He had a tough match [in the third round], five sets, finishing late, and he didn't serve as well as he usually does. Overall, I'm very happy."

Four-time major champion Sinner, who extended his winning streak at hard-court Grand Slam tournaments to 25 matches, took eight of his 17 break opportunities.

Going into the match, Bublik had won all 55 of his service games in the tournament.

Bublik spoke about the importance of holding serve early in the match, but having completed victory over American hopeful Tommy Paul shortly after 1:15 am local time on Sunday morning, he instantly looked out of sorts.

Losing serve in the first game - down to sloppy groundstrokes and a double fault on a break point - set the tone.

After Sinner seized control, his athleticism soaked up the drop shots and underarm serves thrown his way by the unpredictable Bublik.

There was also no let up in the ferocity of the top seed's groundstrokes.

Bublik could not handle the pace being thrown at him, before a double fault on Sinner's first match point summed up his difficult evening.

In the face of such adversity, the ever-entertaining Bublik still managed to play with a smile on his face and shared a joke at the net with Sinner following his defeat.

"You're so good, this is insane. I'm not bad," the 27-year-old said.

Perhaps the only consolation for Bublik was avoiding being at the wrong end of the fastest beating of the tournament.

Surviving three break points to hold serve for 4-1 in the final set helped him slightly prolong the match, taking it past the one hour and 20 minutes in which the Czech 21st seed, Tomas Machac, beat Italy's Luca Nardi in the first round.

Sinner goes on to face the 10th seed Lorenzo Musetti in an all-Italian quarter-final.